Telephone-exchange system.



S. B. WILLIAMS, JR.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 10. 1916.

1 ,%53,,@57v Patented Jan, 15, 1918.

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S. B. WILLIAMS, JR-

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 10, I916.

Patented; Jan 15, 1918.

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ma n %TATE% SAMUEL B. WILLIAMS, JR., 0F BROOKLYN, NEW YORK, ASSIGNOR TO WESTERN ELEC- ERIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION 015 NEW? YORK.

Specification of Letters Patent.

Patented an, 15, 1018.,

Application filed June 10, 1916. Serial No. 102,881.

To all whom it may concern:

I Be itknown that I, SAMUEL B. W'iLLIAMS, Jr., a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems employing operators at the central oliice to establish connections.

Its object is to provide an improved circuit arrangement for associating the operators telephone set with and disconnect ing the same from the connecting circuits.

In accordance with this invention, a listenin key is provided for each connecting circuit, adapted, upon its actuation, to cause the operators telephone set to be connected With the corresponding connecting circuit, means being provided, adapted when the listening key of another connecting circuit is subsequently actuated, for disconnecting the telephone set from any connecting circuit to which it may be connected and cansing it to be connected to the connecting circuit corresponding to the last actuated key. The circuit arrangement of this invention also provides means for preventing the operator from connecting the telephone set to more than one connecting circuit at a time, and for automatically disconnecting the set from a connecting circuit when the calling plug thereof is inserted in the jack of the called line.

The invention will be more readily understood when described with reference to the accompanying drawings, wherein Figure 1 indicates a callin line and the answering end of a connecting circuit, and Fig. 2 a called line and the calling end of a connecting circuit. The invention will be most readily understood by tracing the operations involved in setting up a connection.

Upon the removal of the receiver at sub station A, the line relay 100 is energized over the line circuit. This relay, in attracting its left armature, grounds the multiple 101 of the calling line, and, in attracting its right armature, energizes relays 102, 103, common to the group of lines containing substation A. Relay 102, in attracting its right armature, grounds commutator multiple segment 104 of the group to which substation A belongs, to render the group calling. Relay 103, in attracting its right armature, closes the following circuit to energize the escape magnet 106 of the line finder side switch: free pole of battery, primary stepping magnet 105, escape magnet 106, side-switch arm 1 and its first contact, armature and back Contact of magnet 105, armature and back contact of magnet 107, conductor 108, right armature and front contact of relay 103, conductor 109, conductor 200, outer armature and back contact of slow relay 1201, conductor 202, right armature and back contact of relay 2 17, conductor 209, armature and back contact of the calling supervisory relay E203, conductor 298, left armature and back contact of relay 207 to ground. Magnet 105 does not energize in this circuit. The escape magnet 100 is constructed to release the side switch from position to position, upon its energization.

In position 2, arm 1 connects magnet 105 over the back contacts of magnets 105, 107, to grounded conductor 108, whereupon the finder brush shaft 119 is given a primary anovement by the. operation of magnet 105.

In position 2, arm 2 closes the following circuit for relay 116: free pole of battery, magnet 107, arm 2 and its second contact, left winding of relay 110, armature and back contact of magnet 107 to grounded conductor 108. This relay is adapted to attract its armature upon the closure of this circuit, but magnet 107 remains inert. Relay 116, at its inner armature and front contact, connects the escape magnet 106 over arm 3 and its second contact to the commutator brush 115. When brush 115 encounters the calling commutator scgmei'it 104. now grounded, escape magnet 100 energizes over the following circuit and releases the side switch into position 3: free pole of battery, magnets 105, 106, conductors 117, 118, inner armature and front contact of relay 116, arm 3 and its second contact, conductors 120, 130, commutator brush 115, segment 104, now grounded at the right armature and front contact of relay 102. Arm 1, in moving out of position opens the circuit of magnet 105. thus stopping the primary movement of the finder brush shaft 119 with a set of brushes 110, 111, 112 in operative relation to multiples of the calling line group containing those of the calling line, 101, 113, and 114.

In position 3. relay 116 is energized over the following circuit: free pole of battery, magnets 10:"), 106, conductors 117. 118, arm 2 and its third contact. left winding of relay 116, armature and back contact of magnet 107, grounded conductor 10S. Magnets 105 and 106 do not energize in this circuit. Relay 116, at its outer armature and front contact, closes the following circuit to operate the secondary stepping magnet- 10? to drive the brushes 110, 111 and 112 over the group of multiples containing those of the calling line 101, 113 and 111: free pole of battery, magnet 10?, outer armature and front contact of relay 116, arm 1 and its third contact, armature and back contact of magnet 105, armature and back contact of magnet 10?, to grounded conductor 106. The magnet 107 interrupts the circuit traced through the left winding of relay 116, as well as its own circuit. and this relay therefore yibrates, except when the brush 112 engages the test multiples 11-1 of busy lines, when it is held energized from battery on such terminals, brush 112, conductor 120, arm 3 and its third contact, right winding of relay 116, to ground. \Vhen. however, the brush 112 reaches the calling, line multiple 1H, relay 116 becomes deenergized. and, in retracting its outer armature, opens the circuit of mag net 107, tints stopping the. finder. Since ground is present on multiple 101 of the calling line. the following circuit is closed for escape magnet 106: free pole of battery,

magnets 105. 106. conductors 117, 118, inner armature and back contact of relay 116, arm 5 and its third contact. brush 110, terminal 101 to ground at the left armature and front contact of relay 100. Magnet 106, upon its energization. releases the side switch into position 1. In position -1. the calling line is extended by arms 4 and 5 to the conductors 1'21, 122, whereupon the calling supervisory relay 203 is energized over the calling line circuit.

In position 4, arm 3 of the finder side switch closes the following circuit. to energize the cutoff relay 128 of the calling line: free pole of battery, relay 297, (Fig. 2), conductors 214. 125, arm 3 and its fourth contact, conductor 120. brush 112. terminal 114-, cut-off relay 128. to ground. This potential applied to multiples 114- by brush 112, holds relay 116 of a moving tinder energized by its right winding as the brush 112 of such finder wipes over such multiples, as hereinbefore described. Relay 126, in attracting its armatures. dei nergizes the line relay 100. which, in retracting its left armature, removes the calling condition from the multiples 101 of the calling line. and. in retracting its right armature. decnergizes group relays 102, 103. Relay 102, in retracting its right armature, removes the calling condition from the connnutator multiples 104 of this group.

Relay 203. in attracting its armature, closes the following circuit for relay 201. to light answering lamp 208 to inform the operator of the arrival of the call .t'rec pole of battery, relay 204. conductor 205, armature and front contact of relay 203. conductor 298, left armature of relay 207, spring 206, front contact of relay 207 to ground. Relay 204, in attracting its right armature, closes the following circuit for lamp 20h: free pole of battery, lamp 20b, right armature and front contact of relay 201, conductor 200, left arn'iature and back contact of relay 210, conductor 211, left armature. and back con tact of relay 212, conductor 213, lower armature and back contact of relay 215 to ground.

Upon the lighting of lamp 208, the operator depresses listening key K of the cord circuit. with which lamp 208 is associated, which results in the closure of thefollowing circuit for a relay 216: free pole of battery, relay 216, conductor 217, right armature and front contact of relay 297, conductor 218, springs 219, 2200f key K, conductor 221, contacts 222, in series of the keys of the other cord circuits of this operators position, to ground. Vpon the release of the key K, relay 216 closes a locking circuit for itself, including a relay 225. shunted out until spring 210 breaks with spring 220, as follows: free pole of battery, relay 216, conductor 217, right armature and front contact of relay 207, conductor 218, left armature and front contact of relay 216, left arn'iature and back contact of relay con ductor 224, relay conductor 226, key 7c, armature and back contact of relay 227, conductor springs 229, 220, which make before 220, 210 break, conductor 221, in series through the contacts 223 of the other cord circuits of this operators position, to ground. Relay 225. in energizing, closes the following circuit: free pole of battery, relay 230, conductor 233. relay 234, right armature and front contact of relay 216, conductor right armature and front contact of relay 225 to ground. Relay 230. in attracting its armatures, connects conductors 236. 237, leading to the operators head set, to the talking conductors 231, Relay 234, in attracting its left armature, connects calling supervisory lamp 238 in circuit with interrupter 230, whereupon lamp 238 flashes. which flashing continues until the operator inserts plug I into jack J, when it will remain lighted until the called party answers. Relay 234, in attracting its right armature. closes the following circuit for a relay 212: free pole of battery, left armature and back contact of relay 2-17. conductor 266, relay 212, right armature and front contact of relay 231, conductor 207, now grounded at a means? front contact of relay 297. Relay 212, i'n operating, closes the circuit of register magnet 254 to count the call, and energizes a slow relay 248.

The operator now inquires the number of the wanted party, and inserts the plug P into the jack J of such line, which results in the closure of the following circuit: free pole of battery. relay 215, conductor 241, sleeve of plug sleeve of jack J, conductor 242, cut-off relay 223 to ground. Relay 24.3, in energizing, removes the control of line relay 296 from the called party, and relay 215, in energizing, connects the tip of plug P with conductor 244 to prepare the ringing circuit. Relay 215, in closing contact 246, energizes relay 24:7. Relay 247, in

attracting its right armature, interposes a break in the circuit of finder release magnet 127, thus transferring the control of the release of the finder from the calling party to the operator, and in attracting its left armature, deenergizes relay 212. Relay 212, in retracting its right armature, deenergizes slow relay 248. Before this relay retracts its armatures, the following circuit is closed for a relay 249: free pole of battery, relay 249, conductors 250, 251, right armature and front contact of relay 248, conductor 252, right armature and back contact of relay 212 to ground. Relay 249, in attracting its left armature, locks itself over the following circuit: free pole of battery, relay 249, its left armature and front contact, conductors 253. 207, spring 206, front contact of relay 297 to ground. Relay 249, in attracting its right armature, permanently opens the circuit of register magnet 254:. thus preventing this magnet from being again operated until relay 297 is decnergized, which occurs only upon the release of the finder.

Relay 247, in attracting its left armature, closes the following circuit for relay 227:

free pole of battery, left armature and front pole of battery, lamp 238. left armature and back contact of relay 234, conductors 271, 272, armature and back contactof calling supervisory relay 265, conductor 273, lower armature and front contact 24:6 of relay 215 to ground. Thus lamp 238 remains continuously lighted.

When. relay 248 retracted its left armature, the following circuit was closed for arelay 255, adapted to apply ringing current to the called line: free pole of battery,

left armature and front contact of relay 24:7, conductor 256, left'armature and back contact of relay 2&8, conductors 257, 258, relay 255, conductor 259, armature and back contact of relay 260, conductor 266, armature and back contact of ringing cut-off relay 267, to ground. Relay 255-, in attracting its arma-tures, closes the ringing circuit as follows: free pole of generator 2633, relay 267, upper arn'laturcand front. contact of relay 255, conductor 2 21, upper armature and front contact of relay 215, tip of plug l tip of jack J, line conductor a, condenser a, bell 5, line conductor 03, ring of the jack J, ring of the plug P, conductor 264:, lower armature and front contact of relay 255 to ground.

When the called party removes his receiver, relay 267 is energized, and in attracting its armature. removes the shunt from about relay 260. The circuit traced for re lay then leads from conductor 259 to ground, through relay 260, conductor 250, left armature and front contact of relay 24:9 to ground at s ring 206 and front contact of relay 297. elay 260, in attracting its armature, locks itself to conductor 250 and shunts out relay 255, which, in retracting its armatures, opens the ringing circuit and closes the circuit of calling supervisory relay Ilelay 265, in attracting its armature, cxtinguishes calling supervisory lamp 238.

The parties may now converse, talking current being supplied to the calling party over the windings of relay 203, and to the called party over the windings of relay 265,

the calling and called ends of the connecting circuit being conductively separated, though inductively united, by condensers 268, 269.

If, for any reason, the operator, after depressing key K, desires to listen in on another connecting circuit, without inserting the plug P in jack J, which automatically disconnects her head set from conductors 231, 232 as described, she will depress the listening key K of such connecting circuit. This opens contacts 223, 222 of such key which breaks the locking circuit heretofore traced for relays 216, 225. This results, as before described, in the denergization of relays 216, 225, which, in releasing, deenergize relay 230 which disconnects the head set from conductors 231, 232. When key K is released, the relay corresponding to relay 225 energizes, which results in the energization of the relay 230 of such cord. circuit. This relay connects the head set to the talking conductors of the associated connecting circuit. Since the head set cannot be connected to a connecting circuit until the relay 225 thereof is energized, and since this relay cannot be energized until pressure is removed from the listening key, it follows that it. is impossible for the operator to connect her set: with more than one connecting circuit at a time.

In case it is desired to disconnect the head set from the connecting circuitwith which it is associated without inserting the calling plug 1 of such connecting circuit in the jack J of the called line and without connecting the head set to another connecting circuit. master-listening-out. key IL is depressed. which results in the deenergization of relay 216, of the connecting circuit with which the head set is associated. which relays, in falling back. open the circuit of relay 230. thus disconnecting the head set from the talking conductors 231, 232 of such connecting circuit.

If, upon the conclusion of the conversation, the 'alling party desires to make another call, he may cause the answering super visory lamp 208 to flash intermittently by merely replacing his receiver upon the hook, and again removing it. This is accomplished as follows: The replacement of the receiver by the. party at substation A causes the relay 203 to become decnergized. This relay, in retracting its armature, closes the following circuit: ground, spring 206. left armature of relay 297, conductor 29S, armature and back contact of relay 203, conductor 299, right armature and front contact of relay 247. conductor 274, left armature and front contact of slow relay 201 which holds its armatures attracted for an interval after relay 203 falls back. conductor 275, spring 276 of relay 210, relay 210, free pole of battery. Relay 210, in attracting its right armature. locks itself over the following circuit: free pole of battery. relay 210, spring 276. right armature of relay 210, conductor 27?. right armature and back contact of relay 234, conductor 204', spring 206, and front contact of relay 297. to ground. Relay 210, in attracting its left armature, connects the interrupter 235) to the front contact of relay 201 hen the calling party again removes his receiver. relay 203 be comes energized, and in attracting its armature, energizes relay 20%, as before. Relay 204, in attracting its right armature, connects the answering supervisory lamp 20b to the interrupter 239 over the left armature and front contact of relay 210. The operator thus is informed that the calling party desires another connection. In response to the flashing of this lamp, the operator depresses the listening key K. which results in her head set being connected to conductors 231. 232 connected to the calling line, as hereinbefore described. If the calling party merely replaces his receiver. lamp 208 will remain continuously lighted over the following circuit: free pole of battery, lamp 208, right armature and back contact of relay 204, contact 245 of relay 215 to ground.

The called party can cause the calling supervisory lam 238 to flash by the mere replacement and removal of hls receiver, provided the calling party has restored his receiver. Assume, therefore, that the calling party has restored his receiver and that the called party replaces his receiver and again removes it. The replacement of the receiver energizes relay 27 8 over the following circuit: free pole of battery, relay 278, contact 279, conductor 280, left armature and back contact of relay 204:, conductor 272, armature and back contact of relay 265, conductor 27 3, contact 246 and lower armature of relay 215 to ground. Relay 278, in attracting its left armature, locks itself to conductor 273, and, in attracting its rightarmature, connects interrupter 239 to the from contact of the calling supervisory relay 265. Consequently, when the called party removes his receiver, calling lamp 238 is intermittently lighted over the following circuit: free pole of battery, lamp 238, left armature and back contact of relay 234, conductors 271, 272, armature and front contact of relay 265, right armature and front contact of relay 278, interrupter 239, to ground. The operator, by depressing listening key K, causes her head set to he connected to the talking conductors 231, 232 of the cord circuit, whereupon she may learn the called partys wants.

What is claimed is:

I. In a telephone exchange system, the combination with telephone lines, connecting circuits, listening keys associated therewith, means for associating said lines With said connecting circuits, an operators telephone set, a relay 230 for each connecting circuit adapted when operated to connect said set to the associated connecting circuit, a relay 216 for each connecting circuit adapted to be operated upon the depression of the corresponding key and to prepare a circuitfor said relay 230, a relay 225 adapt ed to complete said circuit, and an energizing circuit therefor closed upon the release of the key.

2. In a telephone exchange system, the combination with telephone lines, connecting circuits, listening keys therefor, means for associating said lines with said connect ing circuits, an operators telephone set, a relay 230 for each connecting circuit adapted when operated to connect said set to the associated ci'innecting circuit, a relay 216 adapted to prepare a circuit for said relay 230. a circuit therefor closed by the depression of the corresponding key and leading in series through normally closed contacts of a plurality of keys of other connecting circuits, and a relay 225 adapted to complete said circuit, said relay being shunted as long as the key is depressed and being operated upon the release of the key to complete said circuit.

3. In a telephone exchange system, the combination with calling and called telephone lines, said called lines terminating in jacks, connecting circuits including calling plugs, means for associating said calling lines with the answering ends of said connecting circuits, an ope ators telephone set, a relay 216 for each connecting circuit controlling the connection of said set with said circuit, a locking circuit for said relay, a circuit for each of said relays closed upon the actuation of the corresponding key whereupon the corresponding relay 216 prepares said locking circuit, a circuit for closing said locking circuit closed when the key is released including normally closed contacts of a plurality of keys of other connecting circuits, a relay 227 adapted to open said locking circuit, and a circuit for said relay closed upon the insertion of said plug in the jack of the called line.

associated with each said circuit for connecting said operators set with said circuit and a circuit for said second relay prepared by said first relay and effective upon the release of said key.

5. In a telephone system, a plurality of connecting circuits, a listening key for each said circuit, an operators set, a relay for each said circuit responsive to the actuation of said key, means controlled by said relay for interconnecting said circuit and said operators set and means for rendering ineffective said means until the release of said key.

In witness whereofil hereunto subscribe my name this 8th day of June, A. D., 1916.

SAMUEL B. WILLIAMS, JR. 

